8 servings

1 (¾- to 1-pound) round Italian loaf, cut into 1-inch cubes (8 cups) 2 tablespoons olive oil, divided 2 pounds sweet Italian sausage, casings removed, divided 1 stick unsalted butter, cut into pieces 3 medium onions, chopped 4 large celery ribs, chopped 5 garlic cloves, minced 4 large eggs, lightly beaten ¾ cup heavy cream, divided ½ cup turkey giblet stock or reduced-sodium chicken broth 1 cup grated Parmigiano-Reggiano (2 ounces) ½ cup coarsely chopped flat-leaf parsley Special Equipment 4-qt shallow ceramic or glass baking dish